Bioprocess Technology

Like other applications of biotechnology, modern bioprocess technology is an extension of ancient techniques for developing useful products by taking advantage of natural biological activities. When our early ancestors made alcoholic beverages, they used a bioprocess: the combination of yeast cells and nutrients (cereal grains) formed a fermentation system in which the organisms consumed the nutrients for their own growth and produced by-products (alcohol and carbon dioxide gas) that helped to make the beverage. Although more sophisticated, today's bioprocess technology is based on the same principle: combining living matter (whole organisms or enzymes) with nutrients under the conditions necessary to make the desired end product.

Bioprocesses have become widely used in several fields of commercial biotechnology, such as production of enzymes (used, for example, in food processing and waste management) and antibiotics. As techniques and instrumentation are refined, bioprocesses may have applications in other areas where chemical processes are now used.

Because bioprocesses use living material, they offer several advantages over conventional chemical methods of production: they usually require lower temperature, pressure, and pH (the measure of acidity); they can use renewable resources as raw materials; and greater quantities can be produced with less energy consumption.

In most bioprocesses, enzymes are used to catalyze the biochemical reactions of whole microorganisms or their cellular components. The biological catalyst causes the reactions to occur, but is not itself changed. After a series of such reactions (which take place in large vessels called fermenters or fermentation tanks), the initial raw materials are chemically changed to form the desired end product. Although it sounds quite simple, this procedure presents two major challenges.

First, the conditions under which the reactions occur must be rigidly maintained. Temperature, pressure, pH, oxygen content, and flow rate are only a few of the variables that must be kept at very specific levels. With the development of automated and computerized equipment, it is becoming much easier to accurately monitor reaction conditions and thus increase production efficiency.

Second, the reactions result in the formation of many unwanted by-products. The presence of contaminating waste material often poses a two-fold problem: how to recover (or separate) the end product in a way that leaves as little residue as possible in the catalytic system (since enzymatic catalysts remain unchanged as they drive reactions, they can be used over and over again); and how to isolate the desired product in pure form.

The many potential uses of biotechnology are developed through laboratory procedures that generally produce only small amounts of useful substances. As advances in bioprocess technology, particularly separation and purification techniques, are made, commercial firms will be able to economically produce these substances in large amounts, and thus make them available for use in medical research, food processing, agriculture, pharmaceutical development, waste management, and numerous other fields of science and industry.